Fluid Mechanics MCQ Set 5

FLUID MECHANICS MCQ SET 5

Q1.The total energy line (TEL) represents:

A) Kinetic head only
B) Pressure head + Velocity head + Datum head
C) Static head
D) Velocity head only

Show Answer

Answer: B) Pressure head + Velocity head + Datum head
Explanation: TEL shows total energy per unit weight of fluid at different points in a flow system.

Q2.The dimension of kinematic viscosity is:

A) L²T⁻¹
B) LT⁻²
C) MLT⁻³
D) L³T⁻¹

 

Show Answer

Answer: A) L²T⁻¹
Explanation: Kinematic viscosity (ν) = Dynamic viscosity (μ) / Density (ρ), giving dimension L²T⁻¹.

Q3.The discharge through an orifice varies as:

A) √head
B) head
C) head²
D) 1/head

Show Answer

Answer: A) √head
Explanation: Q=CdA2ghQ = C_d A sqrt{2gh}Q=Cd​A2gh​; thus discharge is proportional to square root of head.

Q4.The coefficient of discharge (Cd) is:

A) Ratio of actual to theoretical discharge
B) Ratio of theoretical to actual discharge
C) Constant
D) Unity

Show Answer

Answer: A) Ratio of actual to theoretical discharge
Explanation: Cd = Qactual / Qtheoretical; it accounts for energy losses and flow contraction.

Q5.A Pitot tube measures:

A) Static pressure
B) Velocity head
C) Flow velocity
D) Total head

Show Answer

Answer: C) Flow velocity
Explanation: Pitot tube measures stagnation pressure to determine fluid velocity.

Q6.The efficiency of a fluid machine is defined as:

A) Output/Input
B) Input/Output
C) Loss/Input
D) None

Show Answer

Answer: A) Output/Input
Explanation: Efficiency = Useful output energy ÷ Input energy × 100%.

Q7.The pressure difference in a Venturi meter is measured by:

A) Manometer
B) Thermometer
C) Barometer
D) Flow nozzle

Show Answer

Answer: A) Manometer
Explanation: The differential manometer connected to the Venturi measures pressure difference between throat and inlet.

Q8.The drag force on a sphere moving through a fluid depends on:

A) Diameter and velocity
B) Fluid density and viscosity
C) Both A and B
D) None

Show Answer

Answer: C) Both A and B
Explanation: Drag force depends on fluid properties (ρ, μ) and sphere size and velocity.

Q9.The terminal velocity of a particle in a viscous fluid is the velocity at which:

A) Acceleration is maximum
B) Net force is zero
C) Drag is minimum
D) None

Show Answer

Answer: B) Net force is zero
Explanation: Terminal velocity occurs when gravitational and buoyant forces balance viscous drag.

Q10.In a centrifugal pump, the fluid enters the impeller:

A) Radially
B) Axially
C) Tangentially
D) None

Show Answer

Answer: B) Axially
Explanation: Fluid enters the pump impeller axially and leaves radially due to centrifugal action.